Maximum Density Research Articles

Dynamic J-A model improved by waveform scale parameters and R-L type fractional derivatives

PurposeThe purpose of this study is to model the global dynamic hysteresis properties with an improved Jiles–Atherton (J-A) model through a unified set of parameters.Design/methodology/approachFirst, the waveform scaling parameters β, λk and λc are used to improve the calculation accuracy of hysteresis loops at low magnetic flux density. Second, the Riemann–Liouville (R-L) type fractional derivatives technique is applied to modified static inverse J-A model to compute the dynamic magnetic field considering the skin effect in wideband frequency magnetization conditions.FindingsThe proposed model is identified and verified by modeling the hysteresis loops whose maximum magnetic flux densities vary from 0.3 to 1.4 T up to 800 Hz using B30P105 electrical steel. Compared with the conventional J-A model, the global simulation ability of the proposed dynamic model is much improved.Originality/valueAccurate modeling of the hysteresis properties of electrical steels is essential for analyzing the loss behavior of electrical equipment in finite element analysis (FEA). Nevertheless, the existing inverse Jiles–Atherton (J-A) model can only guarantee the simulation accuracy with higher magnetic flux densities, which cannot guarantee the analysis requirements of considering both low magnetic flux density and high magnetic flux density in FEA. This paper modifies the dynamic J-A model by introducing waveform scaling parameters and the R-L fractional derivative to improve the hysteresis loops’ simulation accuracy from low to high magnetic flux densities with the same set of parameters in a wide frequency range.

Characterization of mine spoils for the reclamation of degraded lands of the Jos-Bukuru tin field, central Nigeria

Tin mining operations on the Jos Plateau have left a lasting impact on the environment, resulting in derelict land, mine spoils, and over a thousand abandoned mining ponds. These ponds have become potential hazards, endangering unsuspecting members of the public. This study aims to provide a comprehensive geochemical and geotechnical characterization of the mine spoils to assess their suitability for the reclamation and restoration of the degraded mined lands. The geochemical analysis reveals that the mine spoils exhibit a strong to moderate level of acidity, with a pH range of 3.91 to 5.90 (average: 4.85). Furthermore, they display deficiencies in essential nutrients such as phosphorus (average: 0.02%) and potassium (average: 0.31%), as well as trace elements such as copper (average: 19.15 ppm), manganese (average: 165.15 ppm), and zinc (average: 53.24 ppm). Notably, the mine spoils are enriched in iron (average: 6.31%). These findings highlight the inadequate presence of both micronutrient and macronutrient elements necessary for successful revegetation which is a crucial component of reclamation. Results from the geotechnical tests indicate that the mine spoils possess an average fines content of 56.03%, a mean liquid limit of 38.06%, and a mean plasticity index of 15.52%. Additionally, the average linear shrinkage value is measured at 10%. The average values for maximum dry density (MDD) and optimum moisture content (OMC) are 1.65 g/cm³ and 19%, respectively. The unsoaked California bearing ratio (CBR) averages 34.64%, while the coefficient of permeability for the spoil is approximately 1.24x10-3 mm/sec. Furthermore, the spoils average cohesion (C) was measured to be 12.150 while the mean angle of internal friction is 30.77 KN/M2. These results collectively indicate that mechanical and chemical stabilization, involving the use of lime, fly ash, and other soil-stabilizing agents is imperative for the effective reclamation of the degraded lands using the mine spoils. Such measures if adopted and implemented will mitigate the risk of accidents and drowning incidents from mining ponds and other abandoned pits involving unsuspecting members of the public and will contribute to the overall environmental restoration efforts in the Jos-Bukuru Tin Field.

Aniline tetramer conjugated N-doped graphene aerogel enabling efficient pH-universal aqueous supercapacitors

The development of novel negative electrode (anode) materials for efficient aqueous supercapacitors (SCs) remains appealing yet significantly challenging. Here we propose an aniline tetramer conjugated nitrogen-doped graphene aerogel (AT−NGA) as the anode material, exhibiting a maximum capacitance of 699.1F g−1 under 1 A/g in 1 M H2SO4 as well as a long lifespan of 6,000 cycles at all pH levels. In particular, its capacitive contribution is 94.1 %, superior to the best pseudocapacitive materials known. To evaluate its pH-universality, we assembled three asymmetric SCs, namely, AT−NGA//1 M H2SO4//graphene aerogel, AT−NGA//1 M Na2SO4//NaMnO2-x and AT−NGA//1 M KOH//NiCoFe layered double hydroxide. The acid device delivers maximal energy and power densities of 35.8 mWh g−1 and 13.0 W/g, the neutral device achieves a maximal energy and power densities of 71.8 mWh g−1 and 33.0 W/g, and the base device exhibits a maximal energy and power densities of 48.2 mWh g−1 and 18.0 W/g, respectively. All the SCs display an outstanding cycling performance over 5,000 cycles (especially, 96 % capacitance retention for the acidic device after 12,000 cycles). Our design can also be expanded to prepare other redox-active anode materials for efficient aqueous SC applications.

Tree-Ring Chronologies from the Upper Treeline in the Russian Altai Mountains Reveal Strong and Stable Summer Temperature Signals

Radial tree growth at high-elevation and high-latitude sites is predominantly controlled by changes in summer temperature. This relationship is, however, expected to weaken under projected global warming, which questions the reliability of tree-ring chronologies for climate reconstructions. Here, we examined the growth–climate response patterns of five tree-ring width (TRW) and maximum latewood density (MXD) chronologies of larch (Larix sibirica) from upper-treeline ecotones in the Altai Mountains, which is a key region for developing millennial-long dendroclimatic records in inner Eurasia. The TRW and MXD chronologies exhibited significant year-to-year coherency within and between the two parameters (p < 0.001). While TRW is mostly influenced by temperature changes during the first half of the growing season from June to July (r = 0.66), MXD is most strongly correlated with May–August temperatures (r = 0.73). All seasonal temperature signals are statistically significant at the 99% confidence level, temporally stable back to 1940 CE, the period with reliable instrumental measurements, and spatially representative for a vast area of inner Eurasia between northeastern Kazakhstan in the west, northern Mongolia in the east, southern Russia in the north and northwestern China in the south. Our findings demonstrate the paleoclimatic potential of TRW and especially MXD chronologies and reject any sign of the ´divergence problem´ at these high-elevation, mid-latitude larch sites.

Highly matched electrode for all-solid-state sodium-ion fiber hybrid supercapacitor with wide temperature and high energy density

In order to solve the kinetic mismatch problem of hybrid supercapacitors, a simple and effective assembly technology for wide temperature all-solid-state sodium-ion fiber hybrid supercapacitor is proposed based on anode and cathode with optimal volume capacity ratio and complementary potential windows. Ti3C2Tx fiber anode is produced by wet spinning in acetic acid bath. It reveals an excellent volume capacity of 406 F cm−3, good cycle stability of 90 % retention in 1 M NaClO4 electrolyte, high conductivity of 3303 S cm−1, and tensile strength of 80 MPa. NaV3O8/rGO (NVO/rGO) fiber cathode is obtained by wet spinning and hydrothermal treating, exhibiting high matched volumetric capacitance and improved rate performance. Moreover, a wide temperature all-solid-state sodium-ion fiber hybrid supercapacitor (PVA EGHG NVO/rGO//Ti3C2Tx AFSIC) is assembled using polyvinyl alcohol ethylene glycol hydrogel (PVA EGHG) as separator and electrolyte. The AFSIC shows an outstanding volumetric specific capacitance of 76 F cm−3 at 0.1 A cm−3, and a maximum volumetric energy density of 30.6 mWh cm−3 at a power density of 83.2 mW cm−3. In addition, it can be bend to diverse degrees without significant change in its electrochemical performance. In addition, the AFSIC exhibites exceptional capacitance and outstanding flexibility in a wide temperature range of −40 to 60 °C, showing that the PVA EGHG NVO/rGO//Ti3C2Tx AFSIC has wide prospect in the area of wearable electronic components.

Geotechnical and microstructural analysis of high-volume fly ash stabilized clayey soil and machine learning application

The weak soil stabilization using solid wastes is one of the most common solutions for improving geotechnical characteristics as well as for problematic waste dumping in landfills. The present experimental study aims to examine the effect of high-volume Class-F fly ash on the geotechnical and microstructural properties of clayey soil by adding them in ranges between 5 % and 50 %. The results show that as the amount of fly ash in clayey soil increases, properties like the specific gravity, plasticity index, permeability, optimum moisture content, maximum dry density and free swelling index improves. Moreover, these geotechnical properties were analyzed to develop machine learning models using three different algorithms, namely K-nearest neighbor regression, random forest, and support vector regression, for obtaining the optimum amount of fly ash contents in weak expansive soils. The predicted and experimental results found to be in close-relation for predicting the geotechnical behavior of modified clayey soil. Furthermore, the performance of the ML models degrades as the number of components reduces, with KNN regression consistently outperforming SVR and RF but suffering significantly with fewer components. The results of the testing set in the case of four components are MSE of 77, R² of 0.896, RMSE of 0.846, MAE of 0.327, and SEE of 0.858, indicating precise and consistent predictions. However, the prediction accuracy considering lesser components shows MSE as 262, R² as 0.648, MAE as 5.606, SEE as 16.707, and GPI as 1.056, confirming the elevated error rates. Overall, it has been concluded that combining comprehensive experimental work and machine learning techniques outperforms in enhancing geotechnical data processing, optimized waste contents in weak soils, improves sustainability in construction, saves resources, reduces the possibility of human mistakes, and increases reliability.

The variation of the temperature of maximum density of non-polar solutes in water: insights from the pressure change in a constant volume solution process

The effects of non-polar solutes on the temperature of maximum density (T MD) of water are revisited by means of a molecular dynamics study of TIP4P/2005 water and two examples of spherically symmetric non-polar solutes modelled by same size single Lennard-Jones sites, with weak and strong solute–water dispersive interactions. We have adopted a two-stage strategy to model the solution process at constant pressure to reduce the analysis to the description of the pressure variation in the solution process at constant volume. To this end, the Reaction Field treatment of the Coulombic forces was used so as to be able to decompose the different molecular components to the virial pressure and their spatial variation in terms of the distance to the solute molecule. In this way, we have been able to separate which factors induce the increase of water’s T MD observed for weakly interacting non-polar solutes and the decrease that occurs when the solute is strongly interacting.

Pegylated Viologen Derivatives to Improve Performance of Aqueous Organic Redox Flow Battery

Renewable energy sources like wind and solar power are great alternatives for a clean way to produce electricity but have the inconvenience to fluctuate1. To address this issue and promote the implementation of renewables sources, scientists are developing new ways to store energy while production is at a maximum for a subsequent release when there is demand. Redox flow batteries (RFBs) are the most appropriate solution and are increasingly gaining attention for stationary, large scale electrochemical energy storage2,3. One variation of RFBs are aqueous organic redox flow batteries (AORFBs), where water-soluble organic molecules are use as the redox couple. Viologen type molecules are particularly well-suited as a negative potential species to develop cheaper and better AORFBs with great scalability, reversibility and long-term stability4.In this study, viologen derivatives were synthesized with various N-functional groups to explore the impact of the substituent on their solubility, viscosity and redox potential. We showed that the use of short chains of poly(ethylene glycol) improved the solubility of the viologens derivatives which could lead to batteries with higher capacity. The symmetric viologen (with two identical substituents) provided a great solubility in water and the formal potential was unaffected by the chemical nature of the substituents. We demonstrated that the 1,1’-(bisethylene glycol)-4,4’-bipyridium (PEG2-V-PEG2) showed the most promising properties with a high solubility (2.3 M in 1M KCl) and low viscosity (3.01 mPa*s at 1M). As such, this derivative was selected for further evaluation in an asymmetrical labs-scale RFB prototype cell versus bis(trimethylamoniumpropyl)ferrocene (BTMAP-Fc). The compound was studied at various concentrations to assess the maximum energy density that can be reached and the effect of concentration on cycling life by achieving a comparison to the symmetrical 1,1’-bis(3-sulfonatopropyl)-4,4’-bipyridium (SPr-V-SPr) at 0.5 M. Figure 1: Redox flow battery scheme using Viologen derivative as the negolyte and BTMAP-Fc as the posolyte Reference Shi, X., Qian, Y. and Yang, S. Fluctuation analysis of a complementary wind–solar energy system and integration for large scale hydrogen production. ACS Sustainable Chemistry & Engineering, 8(18), pp.7097-7110. (2020)Sánchez-Díez, E.; Ventosa, E.; Guarnieri, M.; Trovò, A.; Flox, C.; Marcilla, R.; Soavi, F.;Mazur, P.; Aranzabe, E.; Ferret, R., Redox flow batteries: Status and perspective towards sustainable stationary energy storage. Journal of Power Sources, 481, 1-23. (2021)Poullikkas, A., A comparative overview of large-scale battery systems for electricity storage. Renewable and Sustainable energy reviews, 27, pp.778-788. (2013)Gentil, S., Reynard, D. and Girault, H.H. Aqueous organic and redox-mediated redox flow batteries: a review. Current Opinion in Electrochemistry, 21, pp.7-13. (2020) Figure 1

Δ-MnO2 / Carbon Material Nanocomposites for Aqueous Metal-Ion Electrochemical Energy Storage Devices

In this study, we successfully synthesized δ-MnO2/reduced graphene oxide (rGO) and K-doped MnO₂/graphite nanofibers (GNF) nanocomposite cathode materials for Mg/Zn-ion electrochemical energy storage applications. The device based on the δ-MnO2/rGO nanocomposite cathode showed a high operating voltage of 2V. At a power density of 823 W kg−1, it delivered a maximum energy density of 29.8 Wh kg−1. The device displayed impressive discharge capacity and excellent cycling stability even at a low temperature of −20 °C. Additionally, the K-doped MnO₂/GNF electrode exhibited a high specific capacitance of 410.31 F g⁻¹ at a current density of 0.5 A g⁻¹, while also demonstrating superior cycle stability under high current density, retaining 57.0% of the charge/discharge efficiency at 4 A g⁻¹. Furthermore, the device based on the K-doped MnO₂/GNF electrode delivered a high specific capacitance of 32.51 F g⁻¹ at 0.5 A g⁻¹ and maintained 88.2% of the initial capacitance after 20000 cycles.

(Invited) Efficient P-Doping Via Suppressing Bad P−Sn Interaction

The utilization of non-metallic phosphorus (P) doping is recognized for its advantages in enhancing the conductivity of hematite while minimizing recombination. This is attributed to the suppression of electron trapping facilitated by the favorable electron state of P5+. However, our investigation reveals a significant impact on the overall photoelectrochemical (PEC) performance of P-doped Fe2O3 due to tin (Sn) diffusion from the bottom FTO substrate. Upon identifying the unfavorable interaction between the unintentional dopant Sn4+ and intentional dopant P5+, we have developed a straightforward P-doping method. The resulting P:Sn:Ti-Fe2O3 (P:Sn:Ti triple-doped Fe2O3) exhibits a remarkable improvement in photocurrent density, reaching 3.44 mA cm−2 at 1.23 VRHE, surpassing values reported in previous P-doping hematite studies. Following co-catalyst deposition, the NiFeOx/P:Sn:Ti-Fe2O3 photoanode achieves a maximum photocurrent density of 4.30 mA cm−2 at 1.23 VRHE. This study affirms that suppressing the negative interaction between dopants is crucial for significantly enhancing PEC performance.

Photoelectrochemical Oxidation of Glycerol over g-C3N4 Nanosheets Coupled with Metal-Assisted Hybrid Carbon Quantum Dots

Carbon quantum dots (CDs) are the most promising candidates of the carbon family with a size of less than 10nm. They owned superior properties such as high solubility in aqueous medium, low toxicity, biocompatibility, stable photoluminescence, spectral convertor, and act as electron reservoirs. These properties make CDs suitable for photo-electrochemical catalytic applications. Low quantum yield and activity in the visible light spectrum of CDs may restrict their applicability. To address this issue, doping and surface passivation of CDs is the only approach to improve their physicochemical characteristics, visible light absorption, and quantum yield by altering their size and structure. Metals are electron-efficient entities and act as electron donors. As a result, when metal ions are doped into CDs, the charge density and charge transition between the core of the CDs and the metal ions increases. This results in a greater improvement in the physicochemical properties of CDs as compared to non-metal doping[1]. Metal-assisted CDs i.e. hybrid CDs tend to modulate energy band positions, change the electronic structure, increase quantum yield, and generate new emissive traps in CDs. The photoluminescence property of CDs can be enhanced due to the surface plasmonic resonance (SPR) effects of metal nanoparticles (NPs). Hybrid CDs also show better catalytic performance as compared to the pristine CDs. It helps to enhance the active sites on the CDs surface to facilitate catalytic performance.By keeping these properties, the hybrid CDs were effectively utilized in the field of dye decolorization, degradation of water pollutants, storage materials, and as a sensor[2][3]. The photo-assisted electrochemical glycerol valorization is one of the prominent methods for producing value-added chemicals such as glycolic acid. However, it is a challenge to achieve high yield and selectivity of products. This research investigated the fabrication of heterojunction of g-C3N4 (CN) with CDs and Bi-assisted CDs (BiCD) as a sustainable photoactive material. The heterojunction was obtained by incorporating CDs and BiCD (5wt.% each) onto CN nanosheets by in-situ thermal polymerization treatment and named CDCN and BiCDCN. The prepared composite was analyzed by structural (XRD), functional (XPS) microscopic (FESEM, FETEM) spectroscopic (UV-Vis, PL, TRPL, EDS), and photoelectrochemical characterization techniques.The band gap of CN was obtained as 2.78 eV which was reduced to 2.69 eV for CDCN and 2.62eV for BiCDCN, increasing the absorbance in the visible light zone. The existence of CDs and BiCDs was confirmed by, FETEM investigation (Fig.1a). The XPS analysis of the composite revealed the presence of Bi 4f chemical state of bismuth metal. The calculated TRPL lifetime was 0.28ns for BiCDCN and 2.51 ns for CDCN which was lower than that of CN (9.31 ns) suggesting the rapid electron transfer ability of BiCDCN. In the presence of light and glycerol, the composite BiCDCN had the maximum photocurrent density of 12 mA/cm2, followed by CDCN (1.6 mA/cm2) and CN (1.3 mA/cm2) at 1.2 V. The photoelectrochemical oxidation of glycerol was performed at 0.8V for 3h. The detected products were glycolic acid, glyceric, glyoxylic acid, and oxalic acid. The addition of CD to CN increased the glycerol conversion and yield of glycolic acid & glyoxylic acid significantly. The composite exhibited 43% selectivity towards glycolic acid and 34% for glyoxylic acid. The glycerol conversion and yield of these two products were further enhanced by Bi doping. BiCDCN had a total glycerol conversion of 21%, followed by CDCN at 5.7% and CN at 3.8%. The BiCDCN had the highest yield of glycolic acid at 8.9 % and that for CDCN was 2.4 % and 1.2 % for CN (Fig.1b). The glyoxylic acid yield was 7.2%, 2.2%, and 0.8% for BiCDCN, CDCN, and CN, respectively. Figure 1

Scalable Synthesis of Bulk TiO2 Hybrids and Its Li-Storage Properties in “Rocking-Chair” Type Full-Cell Assembly with LiNi0.5Mn1.5O4 Cathode

TiO2 as an anode material in lithium-ion batteries (LIB) has abolished hurdles like irreversibility, cycling stability, rate capability, and energy density, which are vital for electrochemical performance. Conventionally, time-consuming and complex techniques like solvothermal methods are employed to synthesize TiO2. We herein open a new avenue towards a simple, scalable, and eco-friendly synthesis of bulk TiO2 anatase/bronze hybrids from sodium meta-titanate through a facile mechano-chemical and ion-exchange process under different temperature conditions (400, 450, and 500 °C). Structural and morphological features are analyzed through various characterization techniques such as XRD, FE-SEM, HR-TEM, and XPS. The bronze phase’s high reversibility, low redox potential, high current rate performance, and high power capability of the anatase phase make the hybrid attractive for fabricating high power and high energy density Li-ion power packs. The Li insertion/extraction properties are studied in half-cell assembly (Li/TiO2), where all three TiO2 hybrids exhibited promising results with an initial discharge capacity >165 mAh g-1 at a current rate of 0.05 A g-1 along with a capacity retention >90% after 100 cycles. A “rocking-chair” type full-cell configuration with high voltage LiNi0.5Mn1.5O4 cathode is fabricated, in which LNMO/TiO2-400 °C displayed a discharge capacity of ~88 mAh g-1 at a current rate of 0.05 A g-1. Moreover, the full cell exhibited a capacity retention of >70% after 100 cycles with a maximum energy density of 192.75 Wh kg-1. Figure 1

Nanoparticulated Vanadium Oxide on BiVO4 for Boosting Photoelectrochemical Glycerol Oxidation

Hydrogen (H2) has been spotlighted as ideal energy carrier due to its relatively higher energy density compared to fossil fuel and no carbon emissions during the energy generation. However, most of current produced H2 comes from as byproducts in fossil fuel reforming processes. To reduce dependence on fossil fuel in the H2 production process, photoelectrochemical (PEC) water splitting is considered as promising strategy for producing H2 using sustainable resources. Nevertheless, the insufficient efficiency in PEC water oxidation oxygen evolution reaction (OER) has limited overall PEC water splitting system efficiency due to its relatively high oxidation potential and sluggish catalytic kinetics. Furthermore, the low value of generated oxygen has been pointed out as obstacle from an economic perspective. To overcome these challenges, glycerol, byproduct of biodiesel, has been attracted numerous attentions as PEC oxidation resource since it has three hydroxyl groups and relatively lower oxidation potential than OER. Furthermore, glycerol oxygenated value-added products like dihydroxyacetone (DHA) can improve economics of PEC hydrogen production system. Upon these strengths, PEC glycerol oxidation reaction (GOR) provides improved strategy that generates value-added products in anodic part and green energy source (H2) in cathodic part simultaneously, which can replace PEC water splitting. Bismuth vanadate (BiVO4) is one of the most promising transition metal oxide based catalyst for PEC GOR due to its relatively narrow bandgap, high theoretical photocurrent density and deep positive valence band maximum (VBM) position. Additionally, although the surface kinetics of BiVO4 for OER has been sluggish, it potentially would be advantage for GOR with high production rate. However, the relatively instability of BiVO4 in acidic electrolyte during operation and lower selectivity of oxygenated products has hindered their practical application in PEC GOR. To solve these problems, introduction of nanoparticles as cocatalysts has been much studied for ameliorating surface kinetics and passivation the surface of photoanode. However, the interface between nanoparticles and photoanode with poor chemical interaction can induce the higher interfacial resistance and slow charge transfer efficiency rather. In this study, we present in-situ vanadium oxide (VOx) nanoparticle decoration on the surface of BiVO4 (VOx/BiVO4) via selective etching process using alkaline treatment for enhancing PEC GOR and we report the world best photocurrent density based on BiVO4 photoanode for GOR with high selective DHA production. VOx nanoparticles with an average size of 5 nm by selective etching process using alkaline treatment is decorated on the surface of BiVO4. The VOx promotes the surface reaction kinetics via modulating the fermi level and enhanced photovoltage of BiVO4 and improves long-term stability for GOR by compensation of V5+ and Bi3+, which combines both efficiency and stability. Furthermore, the surface decorated photoanode presents a 6.82 mA/cm2 (1.34-fold improvement) photocurrent density at 1.23 V versus the reversible hydrogen electrode (RHE) under 1 sun illumination, which has been attributed enhanced catalytic kinetics with upshifted fermi level and photovoltage of BiVO4. Moreover, the long-term stability of VOx/BiVO4 has been exhibited over 10 hours and the high selectivity for DHA is achieved. This study presents insight into the role vanadium of selective etched VOx on the surface of BiVO4 with low valence state than that of BiVO4 and improving the potential of BiVO4 based catalyst as GOR photoanode for high selective value-added DHA production using solar energy.

Environment-Benign Colloidal Quantum Dots-Modified Dual Photoelectrodes for Self-Biased Photoelectrochemical Water Splitting.

Photoelectrochemical (PEC) water splitting based on colloidal quantum dots (QDs) presents a promising approach for utilizing solar energy to produce green hydrogen energy. Previous research has been mainly focused on the single-photoelectrode QDs-PEC device operated under external bias, while the investigation of dual-photoelectrode configuration for self-biased QDs-PEC system is still lacking. In this work, two types of eco-friendly Cu-AISe/ZnSe:Cu (CZAC) and Mn-AIS/ZnS@Cu (MAZC) QDs were used to respectively sensitize the semiconductor n-type TiO2 and p-type Cu2O photoelectrodes, which acted as the photoanode and photocathode to build a heavy metal-free QDs-based bias-free solar water splitting cell, yielding a maximum photocurrent density of 0.47 mA cm-2 and a solar-to-hydrogen (STH) efficiency of 0.4 % under 1 sun AM 1.5G illumination (100 mW cm-2). Moreover, approximate 692 nmol of H2 and 355 nmol of O2 with molar ratio of ~2 : 1 was detected after two hours of continuous light illumination, demonstrating the effective overall water splitting. This work indicates a significant advancement towards the realization of a cost-effective, efficient and "green" QDs-based artificial solar-to-fuel conversion system.

Design and Microwave Absorption Performance Study of SiC-Fe3O4 Emulsified Asphalt Mixture.

To address the challenges of slow curing speed and suboptimal microwave absorption during the paving of cold-mixed and cold-laid asphalt mixtures, this study introduces SiC-Fe3O4 composite material (SF) into emulsified asphalt mixtures to enhance microwave absorption and accelerate curing via microwave heating. Initially, based on the maximum density curve theory, an appropriate mineral aggregate gradation was designed, and the optimal ratio of emulsified asphalt mixture was determined through mixing tests, cohesion tests, wet wheel wear tests, and load wheel sand adhesion tests. Subsequently, the influence of SF content on the mixing performance of emulsified asphalt mixtures was analyzed through mixing and consistency tests. Finally, the microwave absorption performance of the mixture was evaluated by designing microwave heating tests under different conditions, using temperature indicators and quality indicators. The experimental results indicate that when SF content ranges from 0% to 4%, the mixing performance of the emulsified asphalt mixture meets specification requirements. The dosage of SF, SF composite ratio, and microwave power significantly impact microwave absorption performance, whereas environmental temperature has a relatively minor effect. The optimal mix ratio for the emulsified asphalt mixture is mineral aggregate:modified emulsified asphalt:water:cement = 100:12.8:6:1. The ideal SF dosage is 4%, with an optimal SiC to Fe3O4 composite ratio of 1:1, and a suitable microwave power range of 600-1000 W.

Noncirculating current series resonant converter with pulse frequency modulation

SummaryIn this paper, an asymmetric pulse frequency modulation (APFM) is applied to the full‐bridge series resonant converter with a secondary LC resonant tank. Different from the traditional PFM, the upper and lower switches have complementary gate drivers and the lower switches have constant on time of half‐resonant period in this paper. Thanks to the resonant tank moved to the secondary side with the adopted APFM, the maximum magnetic flux density Bm of a high‐frequency transformer (HFT) is only concerned with the fixed resonant frequency rather than the variable switching frequency. Hence, the switching frequency can be widely regulated, as well as the voltage gain. Furthermore, the circulating current flowing back to the input voltage source in the traditional LC series resonant converter can be eliminated by the APFM, leading to a low resonant current peak value. The operation principles and characteristics of the adopted method are analyzed in detail. Finally, a 500 W/70–120 V to 300 V/21–180 kHz prototype is built, and the experimental results verified the theoretical analysis well.

Textile-Based Membraneless Microfluidic Double-Inlet Hybrid Microbial-Enzymatic Biofuel Cell.

This study reports the development of a textile-based colaminar flow hybrid microbial-enzymatic biofuel cell. Shewanella MR-1 was used as a biocatalyst on the anode, and bienzymatic system catalysts based on glucose oxidase and horseradish peroxidase were applied on an air-breathing cathode to address the overpotential loss in a body-friendly way. A single-layer Y-shaped channel configuration with a double-inlet was adopted. Microchannels of biofuel cells were patterned by silk screen printing with Ecoflex to maintain the flexibility of textile substrates without harm to the human body. The electrodes were fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and a mixture of multiwalled carbon nanotubes and single-walled carbon nanotubes by screen printing. The effects of electrode materials, catalyst type, catalyst concentration, and glucose concentration in the catholyte were investigated to optimize the fuel cell performance. The peak power density (44.9 μW cm-2) and maximum current density (388.9 μA cm-2) of the optimized hybrid biofuel cell were better than those of previously reported textile- or paper-substrate microscale single microbial fuel cells. The developed biofuel cell will be a useful platform as a microscale power source that is harmless to the environment and living organisms.

Antixenosis in Cultivars of Tomato against <i>Helicoverpa armigera</i> (Hubner)

This study on the effect of antixenosis in relation to resistance against Helicoverpa armigera in tomato was carried out at the Entomological Research Farm, LPU, Phagwara during 2020 and 2021. The result showed that the antixenosis effect of four tomato cultivars on plant morphological characters revealed that Rahul cultivar with maximum trichome density in lamina (181 and 183 cm-2), vein (89 and 93 cm), trichome length (132.43 and 136.21 µm) and leaf lamina thickness (0.21 and 0.23 mm). Correlation analysis between morphological character and larval incidence revealed significant negative correlation with trichome density (lamina and vein), trichome length, leaf area and leaf lamina thickness.

Seasonal occurrence of the shoot fly complex on Rabi sorghum in the Marathwada area of Maharashtra

The present study was conducted to investigate the variety and abundance of shoot flies in the Postgraduate Experimental Field, Department of Agricultural Entomology, College of Agriculture, Latur Campus, Maharashtra, India, during rabi season 2020-21. Analysis of insect pest population dynamics indicated that Atherigona soccata attained its maximum population density during the 51st standard meteorological week, with an average of 3.60 maggots per quadrat. Correlation studies exhibited that wind speed had a detrimental impact on the population of A soccata maggots. During the first sampling period of the study, Oscinella sp. achieved its peak population density, with an average of 13.00 maggots per quadrat. Link tests revealed a positive link between the relative humidity before noon and the population of Oscinella sp., but a substantial negative correlation was seen between wind speed and the population. The population of Ectecephala sp. reached its highest level during the second sampling week, with an average of 2.33 maggots per quadrat. Correlation studies demonstrated a substantial negative correlation between wind speed and the population of Ectecephala sp.

Manipulating Interfacial Renovation via In Situ Formed Metal Fluoride Heterogeneous Protective Layer toward Exceptional Durable Sodium Metal Anodes

AbstractSodium metal is regarded as an optimal anode material for high‐energy‐density sodium‐ion batteries (SIBs). However, during the processes of sodium deposition and stripping, the failure of the solid electrolyte interphase (SEI) film leads to the continuous accumulation of inactive sodium, thereby compromising the cycling reversibility of the battery. Here, a novel metal fluoride heterointerface layer is generated and constructed through in situ manipulation of the continuous reaction between TiF4 and metal Na. The reconstructed NaF/TiF3 interface layer, which tightly anchors the sodium metal, effectively suppresses the formation of sodium dendrites during the charge‐discharge process. The highly sodium‐philic TiF3 component exhibits strong binding with Na ions, while NaF reduces the Na+ diffusion energy barrier, significantly enhancing the reaction kinetics. Due to the successful artificial construction of this interface layer, the Na/TiF4 composite electrode demonstrates an exceptional ultra‐long cycling stability of 2370 h in symmetric cells (0.5 mAh cm−2). Density functional theory (DFT) calculations further validate the functionality of each component in the Na/TiF4 protective layer. When paired with NaNi1/3Fe1/3Mn1/3O2 cathode in a pouch cell, it exhibits stability up to 2000 cycles at current densities of 2 C and 4 C, with a maximum energy density output of 483.1 Wh kg−1 (power density: 320.8 W kg−1).